Ḥabash was forced to flee Palestine in 1948, after the State of Israel was established there, and earned a medical degree at the American University of Beirut. In the early 1950s he was active in the “Youth of Vengeance” group, which advocated violent attacks on traditional Arab governments. Ḥabash founded the militant PFLP after his goal to liberate Palestine through Arab unity proved unrealistic following the Arab defeat by Israel in the Six-Day War of 1967 (seeArab-Israeli wars). Under the leadership of Ḥabash, the PFLP staged several airplane hijackings, including the abduction of three Western passenger jets to a Jordanian airstrip in September 1970. These activities destabilized the Jordanian monarchy and triggered King Ḥussein’s crackdown on Palestinian guerrillas operating in Jordan. A bloody civil war followed, in which the PFLP and other guerrillas were driven from the country.

Ḥabash, a Marxist, visited China in 1970 (where Chinese leaders criticized the PFLP’s “foreign operations”) and Moscow in 1972. Following the Yom Kippur War of 1973, Ḥabash became the leading voice of the “Rejection Front,” four Palestinian groups that opposed any diplomatic settlement to the conflict with Israel. He attacked what he called the “defeatist” attitude of the Palestine Liberation Organization’s leadership, whose attempts at reconciliation with King Ḥussein he sharply criticized. Under his leadership the PFLP successfully organized clandestine cells in the Israeli-occupied West Bank and Gaza Strip. Ḥabash stepped down as leader of the PLFP in 2000.